1. Field of the Invention
The present invention relates to a slider-suspension assembly for a magnetic storage system, and more particularly to a multi-piece integrated suspension assembly for use in a magnetic disk storage system.
2. Description of the Related Art
Magnetic disk drives are information storage devices which utilize at least one rotatable disk with concentric data tracks containing the information, a head (or "transducer") for reading data from or writing data to the various tracks, and a head positioning actuator connected to the head for moving it to the desired track and maintaining it over the track centerline during read or write operations. The transducer is attached to an air-bearing slider which is supported adjacent the data surface of the disk by a cushion of air generated by the rotating disk. The slider is mounted on a support arm of the head positioning actuator by means of a suspension.
The suspension provides dimensional stability between the slider and actuator arm, and controlled flexibility in slight vertical as well as pitch and roll motions (gimbaled motions) of the slider during its relative motion above the rotating magnetic disk surface. The suspension generally comprises a load beam, which is mounted to an actuator arm of the head positioning actuator, and a flexure element supported by the load beam which supports the slider. The load beam provides a resilient spring action which biases the slider toward the surface of the disk, while the flexure provides flexibility for the slider as the slider rides a cushion of air in close proximity against the rotating disk. In the past, various suspension structures have been proposed. For those suspensions having flexures with integrated conductor leads for making electrical connections to the sliders mounted thereon, they are sometimes referred to as trace suspension assemblies or integrated suspension assemblies.
With the push for higher recording densities, it becomes a challenge to format the disk surface with narrower data tracks and narrower inter-track spacings in order to pack more data tracks on the disk surface. To meet this challenge, the performance specification requirements for the flexure is more stringent, in addition to the requirements of the other structural and mechanical components of the disk drive system which are relatively easier to achieve and control. For example, it is important that the integrated suspension be constructed of a light weight structure that is dimensionally stable. The flexure of the integrated suspension must be durable in maintaining its flexibility and reliable in accurately and repeatedly positioning the slider with respect to the disk surface such that the densely packed data tracks can be accessed with tight tolerance in slider/track alignment. Further, it is desired to develop smaller integrated suspensions so as to meet the requirement of disk drive systems of smaller physical size. Due to the relatively small physical size and fragile structure of the suspension assembly, it becomes a challenge to develop integrated suspension structures that are designed for manufacturability while achieving the desired performance specifications and yield requirement.
Assignee's U.S. Pat. No. 4,996,623 disclosed a laminated suspension having a flat flexible sheet of material bonded on both sides to patterned metal layers. This suspension includes an arm portion for attachment to the actuator support arm, a slider portion to which the slider is attached, and a link portion interconnecting the arm and slider portions such that the slider portion extends beyond the actuator support arm at its end. The structure of this design is relatively complex.
FIG. 1 depicts an integrated suspension 20 which was disclosed in U.S. patent application Ser. No. 08/365,123. This integrated suspension 20 includes a load beam 22, a flexure 24 of reduced thickness integrally extending from the load beam 22, conductive leads 26, and a slider 30 mounted to the surface of the flexure 24. An intermediate layer of dielectric material 27 separates the leads 26 from the load beam 22 and the flexure material (see FIG. 2), and supports the leads 26 in a suspended manner along some of its sections (see FIG. 3). The leads 26 terminate on the slider 30 in electrical connection to the read and write sensors contained therein. It is noted that the terminations of the leads 26 are routed over the end of the flexure 24 to terminate on the end face 32 of the slider, which makes the leads 26 more prone to damage during manufacturing and subsequent handling of the integrated suspension 20. Also, it has been found that in a disk drive system which implements a stack of integrated suspensions 20 for multiple disks, more vertical height is needed in the actuator stack to accommodate interconnection of the leads and a flex cable from the control electronics of the disk drive system.